The problem:
:'(
Given that it appears to be the only emoticon which contains ' I wonder if it's some string escaping bug in SMF
Unfortunately I don't know when it stopped working, but it surely used to work in the past.
:'( beginning
ending :'(
middle :'( of
:`(
:'-(
:"-(
:_(
:cry:
Tried a bunch with no luck...
There's already too much crying and ranting in the forum
.